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theses

Species interactions are essential to our understanding of community ecology, particularly when we think about how species persist in communities. Compared to competition and predation, the effect of mutualism on the population dynamics and coexistence of species is less well studied. Interactions between plants and pollinators are a model system for studying mutualism. In these interactions, both of the partner species benefit: the bee receives food, and the plant is able to reproduce because the bee moves its gametes to other plants of the same species. This sounds straightforward, but two points make this more complicated. First, most pollen is deposited within just a few flower visits of where it was picked up. From the perspective of the plant, then, successful reproduction hinges on the foraging choices of bees, particularly the sequences in which they visit plants. A second point complicating the plant-pollinator relationship is that many foraging pollinators have a tendency to preferentially visit whichever plant species is most common in a community. If pollinator visits are proportional to plant abundance, then we might expect that sequential visits would be proportional to the square of plant abundance and so it should be really difficult for rare plants to reproduce. In pollen-limited plant communities, the foraging behavior of pollinators might mediate coexistence and competitive exclusion by determining which plants receive conspecific pollen. A key question is whether realistic pollinator foraging behavior promotes coexistence or exclusion. My first two thesis chapters quantify realistic pollinator foraging behavior in response to relative abundances of flowering species, and the spatial arrangement of flowering plants. In my third chapter, I use a simulation model to understand how pollinator foraging behavior impacts the coexistence dynamics of pollen-limited plants. To determine whether pollinators are likely to provide a biologically important coexistence mechanism in nature, I compare my results to bee foraging data from the literature and from a novel experimental analysis.

ETD_8859

Ph.D.

Includes bibliographical references

by Elizabeth Anne Bruninga Socolar

doi:10.7282/T30P13GW

ETD doctoral

The author owns the copyright to this work.